mirror of
https://github.com/FFmpeg/FFmpeg.git
synced 2026-11-06 13:28:17 +00:00
Romain Beauxis
9edc0748b6
Decode one PCM packet carrying AV_PKT_DATA_SKIP_SAMPLES and print how many samples are output, for samples skipped at the start of the frame and padding discarded at its end, alone, together, overlapping, and with a padding larger than the frame. The reference records the current behaviour.
115 lines
3.2 KiB
C
115 lines
3.2 KiB
C
/*
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* This file is part of FFmpeg.
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*
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* FFmpeg is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* FFmpeg is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with FFmpeg; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* Decode one packet carrying AV_PKT_DATA_SKIP_SAMPLES and print how many
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* samples are output, for skips at the start and padding at the end of the
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* frame, alone, together and overlapping.
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*/
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#include <stdio.h>
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#include <string.h>
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#include "libavcodec/avcodec.h"
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#include "libavutil/channel_layout.h"
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#include "libavutil/intreadwrite.h"
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#include "libavutil/macros.h"
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#define FRAME_SAMPLES 1000
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static int decoded_samples(uint32_t skip, uint32_t discard)
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{
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const AVCodec *codec = avcodec_find_decoder(AV_CODEC_ID_PCM_S16LE);
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AVCodecContext *ctx = NULL;
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AVPacket *pkt = NULL;
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AVFrame *frame = NULL;
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uint8_t *side;
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int nb_samples = 0;
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int ret;
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ctx = avcodec_alloc_context3(codec);
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pkt = av_packet_alloc();
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frame = av_frame_alloc();
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if (!ctx || !pkt || !frame) {
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ret = AVERROR(ENOMEM);
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goto end;
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}
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ctx->sample_rate = 48000;
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ctx->pkt_timebase = (AVRational){ 1, 48000 };
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av_channel_layout_default(&ctx->ch_layout, 1);
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ret = avcodec_open2(ctx, codec, NULL);
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if (ret < 0)
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goto end;
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ret = av_new_packet(pkt, FRAME_SAMPLES * 2);
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if (ret < 0)
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goto end;
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memset(pkt->data, 0, pkt->size);
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pkt->pts = 0;
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side = av_packet_new_side_data(pkt, AV_PKT_DATA_SKIP_SAMPLES, 10);
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if (!side) {
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ret = AVERROR(ENOMEM);
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goto end;
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}
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AV_WL32(side, skip);
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AV_WL32(side + 4, discard);
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ret = avcodec_send_packet(ctx, pkt);
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if (ret < 0)
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goto end;
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ret = avcodec_send_packet(ctx, NULL);
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if (ret < 0)
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goto end;
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while ((ret = avcodec_receive_frame(ctx, frame)) >= 0) {
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nb_samples += frame->nb_samples;
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av_frame_unref(frame);
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}
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ret = ret == AVERROR_EOF ? nb_samples : ret;
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end:
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av_frame_free(&frame);
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av_packet_free(&pkt);
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avcodec_free_context(&ctx);
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return ret;
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}
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int main(void)
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{
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static const uint32_t cases[][2] = {
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{ 0, 0 },
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{ 300, 0 },
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{ 0, 400 },
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{ 300, 400 },
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{ 300, 700 },
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{ 300, 800 },
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{ 300, 1100 },
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};
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for (int i = 0; i < FF_ARRAY_ELEMS(cases); i++) {
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int ret = decoded_samples(cases[i][0], cases[i][1]);
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if (ret < 0) {
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fprintf(stderr, "decoding failed: %s\n", av_err2str(ret));
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return 1;
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}
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printf("frame %d skip %4"PRIu32" discard %4"PRIu32": %d samples\n",
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FRAME_SAMPLES, cases[i][0], cases[i][1], ret);
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}
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return 0;
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}
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